The man tipped as the next head of the European Central Bank has come out strongly against German terms for a second bailout of debt-stricken Greece as eurozone finance ministers argued over how to craft a new rescue.

Mario Draghi, the Italian central banker, went before the European parliament to burnish his credentials as successor in October to Jean-Claude Trichet of France. He promptly picked a fight with Berlin which wants private creditors to take losses as part of a second Greek bailout.

Eurozone finance ministers met on Tuesday night in emergency session in Brussels with the clock ticking on the need for agreement on the new rescue plan.

With the €110bn (£97bn) bailout granted to Greece a year ago having failed to stop the rot, the eurozone is under intense pressure to forestall a Greek sovereign default by agreeing a second rescue expected to amount to another €90bn by next week.

"We haven't yet learned how to manage a sovereign default," Draghi told the parliament, taking issue with proposals from the German finance ministry last week. "We call for the avoidance of any credit events."

Draghi suggested that any restructuring of Greek debt involving losses for private creditors would be seen in the financial markets as a default and could trigger a much graver financial crisis gathering momentum across Europe.

"The ECB is not in favour of restructuring or haircuts. We should exclude all concepts that are not purely voluntary or that have any element of compulsion."

Berlin wants to go beyond "voluntary" creditor pledges to Greece, with Wolfgang Schäuble, the German finance minister, last week insisting that holders of Greek debt had to submit to "a quantified and substantial contribution of bondholders to the support effort".

Schäuble was supported by the Dutch, who said the private sector's contribution should amount to €30bn.

The European commission came out behind the ECB. The Frankfurt-based central bank is being tipped to win next week's showdown at a eurozone meeting in Luxembourg ahead of an EU summit which has to sign off on the Greek rescue.